1. Field of the Invention
The present invention relates to an intake-air control device for an internal combustion engine.
2. Description of the Related Art
The intake-air control device for an internal combustion engine includes a throttle valve and a throttle position sensor. The throttle position sensor serves to detect the rotational position of the throttle valve, and recently, a non-contact throttle position sensor is integrated. The non-contact throttle position sensor is effective for improving durability and enhancing detection accuracy.
The non-contact throttle position sensor includes magnetic field generating means and a magnetic field detecting assembly. The magnetic field generating means rotates together with the throttle valve, and generates a detecting magnetic field in which the direction of magnetic field varies according to the rotation of the throttle valve. The magnetic field detecting assembly is fixed corresponding to the magnetic field generating means. The magnetic field detecting assembly includes a sensor member arranged in the detecting magnetic field, and the sensor member generates a detection output corresponding to the rotation in the direction of the magnetic field in the detecting magnetic field.
An intake-air control device for an internal combustion engine in which the non-contact throttle position sensor is integrated is disclosed in JP-A-2004-332635 as the related art. The throttle position sensor shown in the related art employs a magnetoresistive element (MR element) in the sensor member, and the sensor member is arranged inside a cylindrical holder and fixed therein by filling potting resin therein. The cylindrical holder is fixed on a printed board, and a detection output of the sensor member is supplied to a plurality of wirings on the printed board via a signal processing IC, whereby the plurality of wirings on the printed board are connected to a plurality of terminal leads introduced toward the outside.
In the throttle position sensor disclosed in the related art, the sensor member needs to be fixed in the cylindrical holder accurately in a predetermined direction. However, since the sensor member is fixed in the interior of the cylindrical holder with the potting resin, and there is no guiding member that guides the sensor member to the predetermined direction in this cylindrical holder, the direction of the sensor member may be varied and hence error may be generated in the detection output. Since the printed board is arranged between the cylindrical holder and the terminal leads, the number of components is increased, and a step of joining the signal processing IC and the wirings on the printed board and a step of joining the wirings on the printed board and the terminal leads are required in an assembly process.